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Abstract:

A radiation-emitting component includes a semiconductor chip and a
conversion element. The semiconductor chip includes an active layer
suitable for generating electromagnetic radiation and a radiation exit
face. The conversion element includes a matrix material and a luminescent
material. The conversion element is arranged downstream of the radiation
exit face of the semiconductor chip. The matrix material comprises at
least 40 wt. % tellurium oxide and is free of boron trioxide and/or
germanium oxide. A method for producing such a radiation-emitting
component is furthermore stated.

Claims:

1-16. (canceled)

17. A radiation-emitting component comprising: a semiconductor chip
comprising an active layer suitable for generating electromagnetic
radiation and a radiation exit face; a conversion element comprising a
matrix material and a luminescent material, wherein the matrix material
comprises at least 40 wt. % tellurium oxide and is free of boron trioxide
and/or germanium oxide, wherein the conversion element is arranged
downstream of the radiation exit face of the semiconductor chip.

18. The component according to claim 1, wherein the matrix material is
free of boron trioxide.

19. The component according to claim 1, wherein the matrix material is
free of germanium oxide.

20. The component according to claim 1, wherein the conversion element is
arranged directly on the radiation exit face of the semiconductor chip.

21. The component according to claim 1, wherein spacing is arranged
between the conversion element and the radiation exit face of the
semiconductor chip.

30. The component according to claim 1, wherein the conversion element is
formed by a potting compound in which the semiconductor chip is embedded.

31. The component according to claim 1, wherein the conversion element
takes the form of a beam-shaping element.

32. A method for producing a radiation-emitting component, the method
comprising: providing a semiconductor chip that comprises an active layer
suitable for generating electromagnetic radiation and a radiation exit
face; and applying a conversion element onto the radiation exit face of
the semiconductor chip, wherein the conversion element comprises a matrix
material and a luminescent material, wherein the matrix material
comprises at least 40 wt. % tellurium oxide and is free of boron trioxide
and/or germanium oxide.

33. A method according to claim 14, wherein applying the conversion
element involves applying the matrix material directly onto the radiation
exit face of the semiconductor chip and then coating it with the
luminescent material, and the luminescent material sinking into the
matrix material.

34. A method according to claim 15, wherein the matrix material is
deliberately coated non-uniformly with the luminescent material, such
that a uniform emission pattern may be obtained.

Description:

[0001] This patent application is a national phase filing under section
371 of PCT/EP2011/052851, filed Feb. 25, 2011, which claims the priority
of German patent application 10 2010 009 456.0, filed Feb. 26, 2010, each
of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The invention relates to a radiation-emitting component with a
semiconductor chip and a conversion element. The invention further
relates to a method for producing a radiation-emitting component.

BACKGROUND

[0003] Radiation-emitting components with a conversion element are known,
for example, from document WO 97/50132. These components contain a
semiconductor body which emits light (primary light) when in operation
and a conversion element with a luminescent material which converts a
proportion of the primary light into another wavelength range (secondary
light). The color appearance of the light emitted by such a semiconductor
component is the result of additive color mixing of primary light and
secondary light.

[0004] The conversion element may be arranged in various ways downstream
of the semiconductor body. For example, the conversion element consists
of a potting compound, in which the luminescent material is embedded and
which surrounds the semiconductor body. It is further known to arrange a
conversion element with at least one luminescent material downstream of
the semiconductor body.

[0005] A conversion element is conventionally used here which comprises
silicone as matrix material, a luminescent material being introduced into
the matrix material. The conversion element is here fastened onto a
surface of the semiconductor chip by means of an adhesion layer, for
example of an organic adhesive. Silicone, however, exhibits poor thermal
conductivity, which may result in the luminescent material heating up
when the component is in operation, so disadvantageously impairing the
efficiency of the component.

[0007] In one aspect, the present invention provides a radiation-emitting
component which is distinguished by improved dissipation of the heat
arising during operation of the component by the matrix material,
consequent improved efficiency of the component and simultaneously by an
elevated refractive index of the matrix material.

[0008] The invention provides a radiation-emitting component which
comprises a semiconductor chip and a conversion element. The
semiconductor chip comprises an active layer suitable for generating
electromagnetic radiation and a radiation exit face. The conversion
element comprises a matrix material of a tellurium-containing glass and a
luminescent material. The conversion element is arranged downstream of
the radiation exit face of the semiconductor chip.

[0009] The radiation exit face is preferably formed by a major face of the
semiconductor chip. The conversion element is particularly preferably
applied at least onto this major face of the semiconductor chip.

[0010] The semiconductor chip is preferably an LED chip which comprises a
layer sequence which is composed of a number of different layers and
contains an active layer. When the component is in operation, the active
layer preferably emits at least one kind of radiation, for example
ultraviolet, blue or green radiation. The active layer may for example
comprise a pn-junction, a double hetero structure, a single quantum well
structure (SQW structure) or a multi quantum well structure (MQW
structure). Such structures are known to a person skilled in the art and
are therefore not explained in greater detail at this point.

[0011] The semiconductor chip is preferably based on a nitride compound
semiconductor, phosphide compound semiconductor and/or arsenide compound
semiconductor. In the present context, this means that the active
epitaxial layer sequence or at least one layer thereof comprises a
nitride, phosphide and/or arsenide III/V compound material. The compound
material may here comprise one or more dopants and additional
constituents which do not substantially modify the characteristic
physical properties of the compound material.

[0012] The semiconductor chip preferably emits primary radiation of a
wavelength λ0. A major part of the radiation emitted by the
semiconductor chip is preferably emitted from the semiconductor chip
through the radiation exit face. A conversion element is preferably
arranged downstream of the semiconductor chip in the emission direction,
which conversion element contains at least one luminescent material
which, when excited with the wavelength λ0, emits secondary
radiation of another wavelength. In this manner, the component
particularly preferably emits mixed radiation containing the primary
radiation from the semiconductor chip and secondary radiation from the
conversion element.

[0013] Suitable luminescent materials are known to a person skilled in the
art for example from document WO 98/12757 and from document WO 01/65613
A1, the disclosure content of which is in this respect in each case
hereby included by reference.

[0014] In one embodiment the conversion element is arranged directly on
the radiation exit face of the semiconductor chip. Spacing is thus not
provided between the semiconductor chip and conversion element. The
conversion element is preferably fastened onto the radiation exit face of
the semiconductor chip. The conversion element is thus fastened directly
onto a major face of the semiconductor chip, no spacing and/or other
layers or materials being arranged between conversion element and
semiconductor chip.

[0015] For the purposes of the application, a direct arrangement between
for example two layers should be taken to mean an arrangement in which
the layers are arranged or fastened directly adjacent one another,
wherein small air pockets or inclusions of foreign bodies such as for
example dust between these layers arising from the production process
should be disregarded in this respect.

[0016] In a further embodiment, spacing is provided between the conversion
element and the radiation exit face of the semiconductor chip. An
interspace comprising a gas, for example air, is preferably provided
between the conversion element and the radiation exit face.

[0017] In a further embodiment, a deliberately introduced interlayer is
arranged between the chip surface and the matrix, resulting in spacing.
The interlayer is between 0 μm and 10 μm thick, preferably between
one atomic layer and 0.5 μm, ideally between 1 nm and 100 nm. The
interlayer may for example have an antireflection, barrier or optical
filter action. In the case of an antireflection interlayer, the
refractive index is between that of the chip and that of the matrix.

[0019] For example, the matrix material consists of TeO2, in which
the luminescent material is embedded. Alternatively, the matrix material
comprises more than 75 wt. % TeO2 and 9 to 24 wt. % ZnO.

[0020] The luminescent material of the conversion element is embedded in
the matrix material of tellurium-containing glass. Glass advantageously
exhibits better thermal conductivity than the silicone which is
conventionally used, whereby dissipation of the heat arising during
operation by the matrix material is advantageously increased. In this
manner, the heat arising during operation, in particular that arising
during operation by heating of the luminescent material in the conversion
element, may be efficiently dissipated via the matrix material, so
advantageously increasing the efficiency of the luminescent material and
consequently the efficiency of the component.

[0021] Tellurium-containing glasses are furthermore advantageously
distinguished by highly refractive properties, such that such a
conversion element, in particular the matrix material, is distinguished
by an elevated refractive index. Depending on the tellurium content in
the glass matrix, a refractive index of n≧2 is thus possible, for
example.

[0022] In a preferred embodiment, phospho-tellurite glass is used as the
matrix material. Silver phospho-tellurite glass is particularly
preferably used as the matrix material. Depending on the intended use of
the component, the composition of the individual components of the matrix
material relative to one another may here be varied.

[0023] Compositions of the matrix material made for example from
phospho-tellurite glasses are known to a person skilled in the art for
example from document DE 2222771 A1, the disclosure content of which is
hereby explicitly included by reference.

[0024] Alternatively, when a matrix material made from silver
phospho-tellurite glass is used, the silver may be completely or
partially replaced for example by alkali metal or alkaline earth metal
materials. The phosphorus of the matrix material may further be
completely or partially substituted by other glass formers known to a
person skilled in the art, such as for example Sb2O3 and/or
SiO2 and/or WO3 and/or MoO3 and/or Bi2O3 and/or
Mn2O7 and/or PbO. It is likewise possible to replace some of
the tellurium oxide of the matrix material by other glass formers. The
matrix material is preferably RoHS compliant and is free of Pb, As, Cd,
U, Tm.

[0025] In a further preferred embodiment, the matrix material is at least
partially transparent to the radiation emitted by the semiconductor chip.
In the wavelength range of the radiation emitted by the semiconductor
chip, the matrix material preferably exhibits transparency of greater
than 60%, particularly preferably of greater than 80%, preferably of
greater than 95%.

[0026] In a further preferred embodiment, the matrix material is free of
boron oxide and/or germanium oxide.

[0027] A matrix material containing boron oxide and/or germanium oxide
therein has a disadvantageous tendency to crystallise due to segregation
behaviour, whereby the conversion element no longer exhibits transparent
properties. This may advantageously be counteracted by a matrix material
which is free of boron oxide and germanium oxide. Segregation behavior
is, for example, counteracted by a melt combination of TeO2 and
P2O5, thus by phospho-tellurite glasses. Good miscibility is in
particular achieved in that phosphate and tellurite glasses primarily
contain chain structural elements which are relatively similar in bulk,
whereby a virtually homogeneous structure can be achieved.

[0028] In a further preferred embodiment, the matrix material comprises at
least one additional element which increases the refractive index of the
matrix material. Refractive index-increasing compounds known to a person
skilled in the art, such as for example La2O3, may for example
be added to the glass.

[0029] In a further embodiment, the matrix material, in particular the
tellurium-containing glass, is lead-free.

[0030] In a further preferred development, the matrix material comprises
at least one further additional component which exhibits
radiation-absorbing properties. The further additional component
preferably absorbs radiation in the wavelength range λ≦380
nm, preferably radiation in the wavelength range λ≦400 nm,
particularly preferably radiation in the wavelength range
λ≦420 nm. The further additional component preferably
absorbs 20%, preferably 40%, particularly preferably 60% of the radiation
in the stated wavelength range. The component may be arranged in a
further matrix material as an additional layer over the conversion
element or beside the conversion element. The additional layer for
example comprises a component which acts as a UV filter.

[0031] In a further development, the glass-transition temperature
(Tg) of the matrix material is at most 350° C., in particular
≦350° C. In particular, the thermal expansion of the matrix
material changes at the glass-transition temperature (Tg) of at most
350° C.

[0032] In a further preferred development, the matrix material is a
low-melting material. For the purposes of the present application, a
low-melting material is considered to be a material which softens at a
temperature of at most 350° C. This advantageously makes it
possible to join the conversion element directly to the semiconductor
chip by the bond being created between the conversion element and
semiconductor chip at at most 350° C., wherein at such
temperatures the semiconductor chip suffers no damage when the conversion
element is applied onto the radiation exit face of the semiconductor
chip. A bonding wire, for example a gold wire, which is used for
electrical contacting of the semiconductor chip may be completely or
partially embedded in the conversion element.

[0033] In a further preferred embodiment, the matrix material or the
conversion element takes the form of an adhesion layer. Such a matrix
material which is distinguished by a low-melting material may, for
example, be used to adhesively bond a further conversion element, a
radiation-shaping element, for example an optical system or a lens, or a
cover to the semiconductor chip at temperatures of at most 350° C.
In this case, the conversion element is thus distinguished both by
radiation-converting and by adhesion properties.

[0034] In a further preferred development, the conversion element assumes
wafer form, also referred to as plate-like form. The conversion element
is preferably a tellurium-containing glass wafer with luminescent
material embedded therein.

[0035] In a further embodiment, the conversion element takes the form of a
potting compound in which the semiconductor chip is embedded. In this
case, the conversion element preferably completely encloses the
semiconductor chip. There is preferably no spacing between potting
compound and semiconductor chip, wherein small air pockets or inclusions
of foreign bodies such as dust particles between potting compound and
semiconductor chip arising from the production process may occur.

[0036] In a further preferred development, the conversion element takes
the form of a beam-shaping element. For the purposes of the application,
a beam-shaping element should be taken to mean an element which modifies
and/or influences the emission direction of the radiation emitted by the
semiconductor chip. A beam-shaping element should for example be taken to
mean a lens, an optical system or a cover for example containing
scattering particles. The beam-shaping element may preferably be formed
by purposeful shaping or by surface tension in the matrix material on
heating of the matrix material. A low-melting material is preferably
suitable as matrix material for this purpose.

[0037] A method for producing a radiation-emitting component comprising a
semiconductor chip and a conversion element comprises the following
method steps:

[0038] providing a semiconductor chip, which comprises an active layer
suitable for generating electromagnetic radiation and a radiation exit
face, and

[0039] applying a conversion element onto the radiation exit face of the
semiconductor chip, which conversion element comprises a matrix material
of tellurium-containing glass and a luminescent material.

[0040] Advantageous further developments of the method arise in a manner
similar to the advantageous further developments of the component and
vice versa. A component described herein may in particular be produced by
means of the method.

[0041] The conversion element is preferably produced by means of a
sintering method, a mixture of luminescent material and glass powder
being sintered, in particular pressed, in order to minimise air pockets.
Temperatures close to the softening point of the glass are used here.

[0042] In a further preferred embodiment, a liquid melt of the matrix
material prepared from tellurium-containing glass with luminescent
material suspended therein is produced, the liquid melt then being
sprayed such that the conversion element is applied onto the radiation
exit face of the semiconductor chip.

[0043] In a further preferred development, a layer of defined thickness of
luminescent material and optionally further elements may be produced on a
glass substrate, sintering then being performed at a temperature close to
the softening point of the glass.

[0044] In a further preferred development, a luminescent material layer of
luminescent material particles is applied onto the radiation exit face of
the semiconductor chip, wherein tellurium-containing glass is then
deposited from the gas phase into the interspaces between the luminescent
material particles.

[0045] In a further preferred embodiment, a thin layer is produced from
the matrix material directly on the chip or a separate wafer is produced
at relatively high temperatures of above 350° C. At this
temperature, the glass preferably has a viscosity of 107.6
dPas*s≧θ≧10-2 dPas*s, in particular of 104
dPas*s≧θ≧10-2 dPas*s, ideally of 102
dPas*s≧θ≧10-2 dPas*s. A very compact glass layer
containing few bubbles is produced in this way. Said layer is then coated
with luminescent material, for example YAG:Ce, using methods known to a
person skilled in the art. The luminescent material particles then sink
into the glass layer at lower temperatures of below 350° C. In
other words, the matrix material coated with luminescent material is then
heated to such an extent that the glass only slightly softens and the
luminescent material sinks into the glass layer and is enclosed thereby.
The sinking temperature is preferably ≧RT to ≦hemisphere
temperature of the glass, better ≧Tg of the glass to
≦hemisphere temperature of the glass, better ≧softening
temperature of the glass to ≦hemisphere temperature of the glass.
The advantage of sinking is that only low temperatures are necessary and
the luminescent material is not damaged thereby. If, for example, the
matrix material is a low-melting material, the temperatures for sinking
are ≦350° C.

[0046] In the case of a separate wafer, it is possible for the wafer to be
positioned on the chip prior to sinking and so to be simultaneously
adhesively bonded with the chip during the sinking process. The side
coated with luminescent material may here face towards or away from the
chip surface. Coating on both sides and coating of the end faces with the
same or different luminescent materials is also possible.

[0047] In the sinking method, luminescent material may also deliberately
be applied non-uniformly, for example in order to improve the module's
uniformity of colour location over the emission angle. The "yellow ring"
phenomenon which often occurs in white LEDs could, for example, be
attenuated by deliberately non-uniform application of the luminescent
material in a horizontal or lateral direction. The thickness of the
matrix material, for example the glass layer, is preferably less than or
equal to 200 μm, preferably less than or equal to 100 μm, in
particular less than or equal to 50 μm, but at least as thick as the
largest luminescent material particles.

[0048] Methods for embedding a luminescent material into glass are known
to a person skilled in the art for example from document DE 102005023134
A1, the disclosure content of which is hereby explicitly included by
reference in the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Further features, advantages, preferred developments and convenient
aspects of the component and of the method are revealed by the exemplary
embodiments explained below with reference to FIGS. 1 to 7, in which:

[0050] FIGS. 1 to 7 each show a schematic cross-section of an exemplary
embodiment of a component according to the invention.

[0051] Identical or equivalently acting components are in each case
denoted with identical reference numerals. The components illustrated and
the size ratios of the components to one another should not be regarded
as to scale.

[0053] A radiation-emitting component should substantially be taken to
mean a component which is suitable for emitting radiation when in
operation. In particular, radiation emission in operation proceeds in
such components by means of electrical contacting of the components.

[0054] The semiconductor chip 1 is preferably an LED chip (LED:
light-emitting diode). The semiconductor chip 1 is preferably a thin-film
LED. In a thin-film LED, the production substrate, on which the layer
stack for the semiconductor chip 1 was produced, in particular deposited,
is removed in zones or completely.

[0055] The semiconductor chip 1 comprises an active layer suitable for
generating electromagnetic radiation. The active layer of the
semiconductor chip 1 comprises a pn-junction, a double heterostructure, a
single quantum well structure (SQW) or a multi quantum well structure
(MQW) for generating radiation. The term quantum well structure does not
here have any meaning with regard to the dimensionality of the
quantisation. It thus encompasses inter alia quantum troughs, quantum
wires and quantum dots and any combination of these structures.

[0056] The semiconductor chip 1 is preferably based on a nitride,
phosphide or arsenide compound semiconductor. In the present context,
based on a nitride, phosphide or arsenide compound semiconductors means
that the active epitaxial layer sequence or at least one layer thereof
comprises a III/V semiconductor material with the composition
InxGayAl.sub.1-x-yP, InxGayAl.sub.1-x-yN or
InxGayAl.sub.1-x-yAs, in each case with 0≦x, y≦1
and x+y≦1.

[0057] The semiconductor chip 1 comprises a radiation exit face 11. The
radiation exit face 11 is preferably formed by a major face of the
semiconductor chip 1. A major face should, for example, be taken to mean
the top of the semiconductor chip 1.

[0058] Means (not shown) for improving outcoupling of the radiation
generated in the active layer may preferably be provided on the radiation
exit face 11 of the semiconductor chip 1. Means for improving outcoupling
should essentially be taken to mean surface patterning. In particular,
light outcoupling may be improved by microprism patterning or increasing
the roughness of the radiation exit face 11. For example, if the
radiation exit face 11 is roughened, this results in the formation of an
irregular surface which improves the outcoupling of light from the
component, so advantageously increasing the efficiency of the
semiconductor chip 1.

[0059] A conversion element 2 is arranged on the radiation exit face 11 of
the semiconductor chip 1. The conversion element 2 is preferably arranged
directly on the radiation exit face 11 of the semiconductor chip 1. In
particular, the conversion element 2 is fastened onto the radiation exit
face 11, in particular is joined mechanically and form-fittingly to the
radiation exit face 11. The conversion element 2 preferably at least in
part covers the light exit face 11 of the semiconductor chip 1. The
conversion element 2 particularly preferably completely covers the
radiation exit face 11 of the semiconductor chip 1.

[0060] The conversion element 2 comprises a matrix material 2a made from
tellurium-containing glass and a luminescent material 2b. The luminescent
material 2b is preferably distributed substantially uniformly in the
matrix material 2a. In this way, color non-uniformities over the emission
angle of the radiation emitted by the component may be reduced, so
advantageously resulting in a uniform emission pattern for the radiation
emitted by the component.

[0061] The semiconductor chip 1 preferably emits primary radiation with a
wavelength λ0. The luminescent material 2b in the conversion
element 2 preferably absorbs at least some of the radiation of wavelength
λ0 and emits secondary radiation of another wavelength. In
this way, a component may be obtained which emits mixed radiation
containing both the primary radiation from the semiconductor chip 1 and
the secondary radiation from the luminescent material 2b.

[0062] By means of a conversion element 2 arranged on the radiation exit
face 11 of the semiconductor chip 1, it is possible to modify, in
particular purposefully adjust, the color location of the radiation
emitted by the semiconductor chip 2. The color location is essentially
taken to mean the numerical values which describe the colour of the
radiation emitted by the component in the CIE color space.

[0063] By purposefully selecting the luminescent material 2b, the color
location of the radiation emitted by the semiconductor chip 1 may be
purposefully corrected, so advantageously resulting in a desired color
location of the radiation emitted by the component 10.

[0064] The conversion element 2 may contain more than one luminescent
material 2b. Using more than one luminescent material 2b enables accurate
color selection of the color location of the radiation emitted by the
component, so in particular making it possible purposefully to achieve a
desired color location of the mixed radiation emitted by the component.
The mixed radiation of the radiation emitted by the component is
preferably located in the white region of the color space.

[0065] Suitable luminescent materials which may be used in such conversion
elements are known to a person skilled in the art for example from
document WO 98/12757 and from document WO 01/65613 A1, the content of
which is in this respect in each case hereby included by reference.

[0067] A matrix material 2a of glass advantageously exhibits improved
thermal conductivity in comparison with the silicone matrix material used
conventionally. Thanks to improved thermal conductivity of the matrix
material, heating of the luminescent material 2b when in operation may
advantageously be reduced, since the heat arising during operation may be
purposefully dissipated away from the luminescent material 2b by the
matrix material. The luminescent material exhibits improved efficiency
when in operation, whereby the efficiency of the component is
advantageously improved.

[0068] Tellurium-containing glasses are preferably used as the matrix
material 2a as they are highly refractive. Conversion elements 2 may be
obtained in this manner which are distinguished in particular by an
elevated refractive index of the matrix material 2a. Depending on the
tellurium content in the matrix material, refractive indices of
n≧2 may be enabled in this manner.

[0069] The matrix material 2a preferably comprises phospho-tellurite
glass. The matrix material 2a particularly preferably comprises silver
phospho-tellurite glass. The composition of the individual components of
the conversion element is here preferably variable. In addition, silver
may be completely or partially replaced by for example alkali metal or
alkaline earth metal and/or phosphorus may be completely or partially
substituted by other glass formers known to a person skilled in the art
such as SbO2 or SiO2. It is alternatively possible partially to
replace tellurium oxide by other glass formers.

[0070] The matrix material 2a is preferably transparent to the radiation
emitted by the semiconductor chip 1. The matrix material 2a is preferably
free of boron oxide and germanium oxide.

[0071] A matrix material 2a containing boron oxide and/or germanium oxide
therein has a disadvantageous tendency to crystallise due to segregation
behaviour, whereby the conversion element 2a no longer exhibits
transparent properties. This may advantageously be counteracted by a
matrix material which is free of boron oxide and germanium oxide.

[0072] The matrix material 2a is preferably lead-free.

[0073] The matrix material 2a is preferably a low-melting material, in
particular a low-melting tellurium-containing glass. As a result, the
conversion element 2 may be joined form-fittingly to the radiation exit
face 11 of the semiconductor chip 1 directly during production of the
component 10. The matrix material with the luminescent material contained
therein is softened at such a low temperature that the bond between
conversion element 2 and semiconductor chip 1 is created at at most
350° C. Damage to the semiconductor chip during the process of
applying the conversion element onto the chip may consequently be
avoided. A bonding wire, for example used for electrical contacting of
the semiconductor chip 2, may here also be completely or partially
embedded in the conversion element 2.

[0074] In the exemplary embodiment of FIG. 1, the conversion element 2 is
in wafer form. The conversion element 2 preferably has a thickness in a
range between preferably 1 μm and 200 μm, better between 5 μm
and 100 μm, preferably between 10 μm and 50 μm, preferably
between 25 μm and 30 μm, ideally substantially 30 μm.

[0075] The conversion element 2 in wafer form advantageously covers at
least 80% of the radiation exit face 11 of the semiconductor chip 1. The
extent of the conversion element 2 in wafer form is particularly
preferably adapted to the extent of the conversion element 1. The base
area of the conversion element 2 is preferably identical or virtually
identical to the base area of the semiconductor chip 1.

[0076] The luminescent material 2b is preferably embedded in the matrix
material 2a by means of a fusion process and/or of a sintering process.
The luminescent material 2b is, for example, suspended in the matrix
material 2a and then screen printed. A method for embedding a luminescent
material in a matrix material, in particular in glass, is known to a
person skilled in the art for example from document DE 102005023134 A1,
the disclosure content of which is hereby explicitly included by
reference in the present application.

[0077] A method for producing a radiation-emitting component according to
the exemplary embodiment of FIG. 1 for example comprises the following
method steps:

[0078] providing the semiconductor chip 1, which comprises an active layer
and a radiation exit face 11, and

[0080] The exemplary embodiment of FIG. 2 differs from the exemplary
embodiment of FIG. 1 in that the conversion element 2 takes the form of a
beam-shaping element. In particular, the conversion element 2 has the
shape of a convex lens. The conversion element 2 thus already takes the
form of an integral lens, wherein the lens may for example arise from
purposeful shaping or from the surface tension of the glass on heating of
the conversion element 2.

[0081] The radiation emitted by the semiconductor chip 1 may be
purposefully guided by such a conversion element 2 shaped as a lens or
beam-shaping element. In particular, the emission angle of the radiation
emitted by the semiconductor chip 1 may be purposefully modified and/or
corrected in this way. The conversion element 2 in this way has an
influence inter alia on the emission pattern and directionality and on
the color location of the radiation emitted by the component. In
particular, the color location is purposefully modified by the
luminescent material 2b embedded in the conversion element 2, while the
emission pattern and directionality are influenced by the shaping of the
conversion element 2.

[0082] Furthermore, in contrast to the exemplary embodiment of FIG. 1, the
conversion element of the exemplary embodiment of FIG. 2 comprises an
additional element 2c which is likewise preferably uniformly embedded and
distributed in the matrix material 2a of the conversion element 2. The
additional element 2c preferably increases the refractive index of the
matrix material 2a. A refractive index-increasing element is for example
La2O3, which is added to the matrix material 2a.

[0084]FIG. 3 shows a further exemplary embodiment of a component 10 which
comprises a semiconductor chip 1 and a conversion element 2. In contrast
to the exemplary embodiment shown in FIG. 1, the conversion element 2 of
FIG. 3 is formed by a potting compound in which the semiconductor chip 1
is embedded. In particular, the semiconductor chip 1 is advantageously
completely enclosed by the conversion element 2. Only a fastening side,
which is preferably located on the opposite side of the semiconductor
chip 1 from the radiation exit face 11, is free of conversion element 2.
As a result, the component 10 may for example be arranged on and
electrically and mechanically connected to a carrier, a circuit board or
a PCB (Printed Circuit Board).

[0085] In contrast to the exemplary embodiment shown in FIG. 1, in the
exemplary embodiment of FIG. 3 an additional layer 3 is arranged
downstream of the conversion element 2, wherein the additional layer 3
preferably comprises a component which is uniformly embedded in the
additional layer 3. The distribution of the component in the additional
layer 3 is preferably substantially uniform. The component preferably
exhibits radiation-absorbing properties. The component particularly
preferably absorbs radiation in the wavelength range λ≦380
nm, preferably in the wavelength range λ≦400 nm, ideally in
the wavelength range λ≦420 nm. In this way, organic
components of the radiation-emitting component 10, such as for example a
plastics housing, may be protected from shortwave radiation and any
consequent damage such as for example discoloration.

[0087]FIG. 4 shows a further exemplary embodiment of a radiation-emitting
component 10, which in contrast to the exemplary embodiment shown in FIG.
3, comprises a conversion element 2 which takes the form of a potting
compound, wherein the potting compound additionally takes the form of a
beam-shaping element. In particular, the potting compound 2 has the shape
of a convex lens. In this way, the radiation emitted by the semiconductor
chip 1 may be purposefully modified or corrected with regard to its
emission pattern and directionality.

[0088] A luminescent material 2b and an additional element 2c, which
increases the refractive index of the matrix material 2a, are furthermore
embedded in the matrix material 2a of the conversion element 2. The
components embedded in the matrix material 2a are preferably
substantially uniformly distributed in the matrix material 2a.

[0089] An additional layer 3 comprising a component which exhibits
radiation-absorbing properties is preferably arranged downstream in the
conversion element 2. The additional layer 3 preferably takes the form of
a potting compound, wherein the potting compound, like the conversion
element 2, additionally takes the form of a beam-shaping element.

[0091] In the exemplary embodiment of FIG. 5, in contrast to the exemplary
embodiment shown in FIG. 3, a beam-shaping element 4 is arranged on the
conversion element 2. In the present case, the conversion element 2
accordingly does not itself take the form of a beam-shaping element, but
instead an additional beam-shaping element 4 is used. In particular, the
beam-shaping element 4 is arranged on the side of the conversion element
2 remote from the semiconductor chip 1. The beam-shaping element 4 is
thus arranged on the radiation exit face 11 of the semiconductor chip 1.
The beam-shaping element 4 is preferably an optical system, a lens and/or
a cover.

[0092] The beam-shaping element 4 may be adhesively bonded to the
semiconductor chip 1 for example by means of the conversion element 2. In
this case, the conversion element 2 preferably comprises a low-melting
glass, such that, when the matrix material 2a is heated, the beam-shaping
element 4 may be mechanically and form-fittingly joined to the conversion
element 2.

[0093] In this way, the semiconductor chip 1 may be joined form-fittingly
to the matrix material 2 and to the beam-shaping element 4. In the
present case, the conversion element 2a is thus used as an adhesion
layer, such that an additional adhesion layer is advantageously not
required.

[0094] The beam-shaping element 4 may moreover be a further conversion
element which for example comprises a matrix material made from glass, a
vitreous ceramic or a ceramic. The further conversion element may here
comprise a luminescent material which is suitable for converting the
radiation of one wavelength emitted by the semiconductor chip into
radiation of another wavelength. In this way, a component may preferably
be obtained which emits mixed radiation, wherein the mixed radiation is
composed of at least three different wavelength ranges, namely the
wavelength range of the radiation emitted by the semiconductor chip 1,
the wavelength range of the radiation converted by the conversion element
2 and the wavelength range of the radiation converted by the further
conversion element.

[0096] In the exemplary embodiment of FIG. 6, in contrast to the exemplary
embodiment shown in FIG. 1, the conversion element 2 takes the form of a
multilayer element. The conversion element 2 preferably comprises a first
layer 21 and a second layer 22. The first layer 21 preferably takes the
form of an adhesion layer. For example, the first layer 21 comprises the
matrix material without luminescent material embedded therein. The second
layer 22 preferably comprises the matrix material 2a and the luminescent
material 2b embedded therein. Alternatively, the second layer 22 may also
be an external conversion element, such as for example a vitreous ceramic
with luminescent material.

[0097] The second layer 22 may here be adhesively bonded to the
semiconductor chip 1 by means of the first layer 21. In this case, the
second layer 22 preferably comprises a low-melting glass, such that, when
the second layer 22 is heated, the first layer 21 may be mechanically and
form-fittingly joined to the semiconductor chip 1.

[0099] In the exemplary embodiment of FIG. 7, in contrast to the exemplary
embodiment shown in FIG. 1, spacing is arranged between the conversion
element 2 and the semiconductor chip 1, such that an interspace 5 is
formed between conversion element 2 and semiconductor chip 1. A gas, for
example air, is preferably arranged in the interspace 5.

[0100] The semiconductor chip 1 and the conversion element 2 are arranged
for example on a carrier 6. The conversion element 2 may here surround
the semiconductor chip 1 in spaced manner. Alternatively, the
semiconductor chip 1 may be arranged in a housing (not shown), wherein
for example areas of the housing serve as a bearing surface for the
conversion element 2, such that spacing may be achieved in this manner
between conversion element 2 and semiconductor chip 1.

[0102] The description made with reference to exemplary embodiments does
not restrict the invention to these embodiments, rather the invention
encompasses any novel feature and any combination of features, including
in particular any combination of features in the claims, even if this
feature or this combination is not itself explicitly indicated in the
claims or exemplary embodiments.

Patent applications by Angela Eberhardt, Augsburg DE

Patent applications by Ewald Poesl, Kissing DE

Patent applications by Joachim Wirth-Schoen, Guenzburg DE

Patent applications by OSRAM AG

Patent applications by OSRAM Opto Semiconductors GmbH

Patent applications in class SEMICONDUCTOR IS AN OXIDE OF A METAL (E.G., CUO, ZNO) OR COPPER SULFIDE

Patent applications in all subclasses SEMICONDUCTOR IS AN OXIDE OF A METAL (E.G., CUO, ZNO) OR COPPER SULFIDE